Biopsy apparatus with vacuum relief

ABSTRACT

A disposable tissue removal device comprising a cutting element mounted to a handpiece. The cutting element includes an outer cannula defining a tissue-receiving opening and an inner cannula concentrically disposed within the outer cannula. The outer cannula has a trocar tip at its distal end and a cutting board snugly disposed within the outer cannula. The inner cannula defines an inner lumen that extends the length of the inner cannula and terminates in an inwardly beveled, razor-sharp cutting edge. The inner cannula is driven by both a rotary motor and a reciprocating motor. At the end of its stroke, the inner cannula makes contact with the cutting board to completely sever the tissue. An aspiration vacuum is applied to the inner lumen to aspirate excised tissue through the inner cannula and into a collection trap that is removably mounted to the handpiece. The rotary and reciprocating motors are hydraulically powered through a hydraulic circuit. The hydraulic circuit includes a foot pedal that initiates aspiration vacuum, rotary motion and reciprocation of the inner cannula. The hydraulic circuit is configured so that the inner cannula closes the tissue-receiving opening before the foot pedal is depressed and automatically after the foot pedal is released.

FIELD OF THE INVENTION

This invention relates to biopsy instruments and methods for taking abiopsy. More specifically, this invention relates to disposable biopsydevices for removing several tissue samples using a single insertion.

BACKGROUND OF THE INVENTION

In the diagnosis and treatment of breast cancer, it is often necessaryto remove multiple tissue samples from a suspicious mass. The suspiciousmass is typically discovered during a preliminary examination involvingvisual examination, palpitation, X-ray, MRI, ultrasound imaging or otherdetection means. When this preliminary examination reveals a suspiciousmass, the mass must be evaluated by taking a biopsy in order todetermine whether the mass is malignant or benign. Early diagnosis ofbreast cancer, as well as other forms of cancer, can prevent the spreadof cancerous cells to other parts of the body and ultimately preventfatal results.

A biopsy can be performed by either an open procedure or a percutaneousmethod. The open surgical biopsy procedure first requires localizationof the lesion by insertion of a wire loop, while using visualizationtechnique, such as X-ray or ultrasound. Next, the patient is taken to asurgical room where a large incision is made in the breast, and thetissue surrounding the wire loop is removed. This procedure causessignificant trauma to the breast tissue, often leaving disfiguringresults and requiring considerable recovery time for the patient. Thisis often a deterrent to patients receiving the medical care theyrequire. The open technique, as compared to the percutaneous method,presents increased risk of infection and bleeding at the sample site.Due to these disadvantages, percutaneous methods are often preferred.

Percutaneous biopsies have been performed using either Fine NeedleAspiration or core biopsy in conjunction with real-time visualizationtechniques, such as ultrasound or mammography (X-ray). Fine NeedleAspiration involves the removal of a small number of cells using anaspiration needle. A smear of the cells is then analyzed using cytologytechniques. Although Fine Needle Aspiration is less intrusive, only asmall amount of cells are available for analysis. In addition, thismethod does not provide for a pathological assessment of the tissue,which can provide a more complete assessment of the stage of the cancer,if found. In contrast, in core biopsy a larger fragment of tissue can beremoved without destroying the structure of the tissue. Consequently,core biopsy samples can be analyzed using a more comprehensive histologytechnique, which indicates the stage of the cancer. In the case of smalllesions, the entire mass may be removed using the core biopsy method.For these reasons core biopsy is preferred, and there has been a trendtowards the core biopsy method, so that a more detailed picture can beconstructed by pathology of the disease's progress and type.

The first core biopsy devices were of the spring advanced, “Tru-Cut”style consisting of a hollow tube with a sharpened edge that wasinserted into the breast to obtain a plug of tissue. This devicepresented several disadvantages. First, the device would sometimes failto remove a sample, therefore, requiring additional insertions. This wasgenerally due to tissue failing to prolapse into the sampling notch.Secondly, the device had to be inserted and withdrawn to obtain eachsample, therefore, requiring several insertions in order to acquiresufficient tissue for pathology.

The biopsy apparatus disclosed in U.S. Pat. No. 5,526,822 to Burbank, etal was designed in an attempt to solve many of these disadvantages. TheBurbank apparatus is a biopsy device that requires only a singleinsertion into the biopsy site to remove multiple tissue samples. Thedevice incorporates a tube within a tube design that includes an outerpiercing needle having a sharpened distal end for piercing the tissue.The outer needle has a lateral opening forming a tissue receiving port.The device has an inner cannula slidingly disposed within the outercannula, and which serves to cut tissue that has prolapsed into thetissue receiving port. Additionally, a vacuum is used to draw the tissueinto the tissue receiving port.

Vacuum assisted core biopsy devices, such as the Burbank apparatus, areavailable in handheld (for use with ultrasound) and stereotactic (foruse with X-ray) versions. Stereotactic devices are mounted to astereotactic unit that locates the lesion and positions the needle forinsertion. In preparation for a biopsy using a stereotactic device, thepatient lies face down on a table, and the breast protrudes from anopening in the table. The breast is then compressed and immobilized bytwo mammography plates. The mammography plates create images that arecommunicated in real-time to the stereotactic unit. The stereotacticunit then signals the biopsy device and positions the device forinsertion into the lesion by the operator.

In contrast, when using the handheld model, the breast is notimmobilized. Rather the patient lies on her back and the doctor uses anultrasound device to locate the lesion. The doctor must thensimultaneously operate the handheld biopsy device and the ultrasounddevice.

Although the Burbank device presents an advancement in the field ofbiopsy devices, several disadvantages remain and further improvementsare needed. For example, the inner cutter must be advanced manually,meaning the surgeon manually moves the cutter back and forth by lateralmovement of a knob mounted on the outside of the instrument or by one ofthe three pedals at the footswitch. Also, the vacuum source that drawsthe tissue into the receiving port is typically supplied via a vacuumchamber attached to the outer cannula. The vacuum chamber defines atleast one, usually multiple, communicating holes between the chamber andthe outer cannula. These small holes often become clogged with blood andbodily fluids. The fluids occlude the holes and prevent the aspirationfrom drawing the tissue into the receiving port. This ultimatelyprevents a core from being obtained, a condition called a “dry tap.”

In addition, many of the components of the current biopsy devices arereusable, such as the driver portions, which control the outer and innerneedles. This poses several notable disadvantages. First, the reusableportion must be cleaned and/or sterilized. This increases the timenecessary to wrap up the procedure, which ultimately affects the cost ofthe procedure. In addition, the required clean-up and/or sterilizationof reusable parts increases the staffs' potential exposure to bodytissues and fluids. Finally, the reusable handle is heavy, large andcumbersome for handheld use.

A further disadvantage is that current biopsy devices comprise an opensystem where the tissue discharge port is simply an open area of thedevice. A surgical assistant must remove the tissue from the opencompartment using forceps and place the tissue on a sample plate. Thisritual must be followed for every sample and, therefore, multipleoperators are required. In addition, the open system increases theexposure to potentially infectious materials, and requires increasedhandling of the sample. As a practical matter, the open system alsosubstantially increases the clean-up time and exposure, because asignificant amount of blood and bodily fluid leaks from the device ontothe floor and underlying equipment.

Additionally, when using the current biopsy devices, physicians haveencountered significant difficulties severing the tissue. For instance,the inner cutter often fails to completely sever the tissue. When theinner cutting needle is withdrawn, no tissue sample is present (drytap), and therefore, reinsertion is required. In the case of the Burbankapparatus, the failure to completely sever the tissue after the firstadvancement of the inner cutter results in a necessary secondadvancement of the inner cutter. In this event, the procedure isprolonged, which is significant because the amount of trauma to thetissue and, ultimately, to the patient is greatly affected by the lengthof the procedure. Therefore, it is in the patient's best interest tominimize the length of the procedure by making each and every attempt atcutting the tissue a successful and complete cut.

Additionally, when using the “tube within a tube” type biopsy device,the inner cutter can lift up into the tissue receiving opening duringcutting. This lifting causes the inner cutter to catch on the edge ofthe tissue receiving opening, which ultimately results in an incompletecut and dulling of the blade, rendering the blade useless.

Also, prior devices often produce small tissue samples. As the innercutter advances, the cutting edge not only starts to sever the tissue,it also pushes the tissue in front of the cutter. This results in atissue sample that is smaller than the amount of tissue drawn into thetissue receiving opening.

An additional disadvantage of the prior devices is presented by thecomplexity of the three-pedal footswitch. Prior devices utilized athree-pedal footswitch; one pedal for advancing the inner cannula,another pedal for retracting the inner cannula, and a third pedal forturning on the aspiration. Operation of the three pedals is difficultand awkward.

These disadvantages become even more significant when using the handheldbiopsy device. For instance, the physician must operate the biopsydevice and the ultrasound probe simultaneously making it particularlydifficult to manually advance of the inner cutter. In addition, when anassistant is required to remove each sample from the open dischargeport, use of the handheld device becomes even more awkward. Due to thesedisadvantages, many physicians have declined to use the handheld models.

This is unfortunate because, some lesions that can signify the possiblepresence of cancer cannot be seen using the stereotactic unit. In thesecases, the doctor must resort to either the handheld device or opensurgical biopsy. Due to the difficulties associated with the handhelddevice, doctors often choose the open surgical biopsy, which isparticularly unfortunate because a majority of the lesions that cannotbe seen using the stereotactic unit turn out to be benign. This meansthat the patient has unnecessarily endured a significant amount of painand discomfort; not to mention extended recovery time and disfiguringresults. In addition, the patient has likely incurred a greaterfinancial expense because the open surgical technique is more difficult,time consuming and costly, especially for those patient without healthinsurance.

The disadvantages of the open surgical technique coupled with the oddsthat the lesion is benign present a disincentive for the patient toconsent to the biopsy. The added discomfort alone is enough to causemany patients to take the risk that the lesion is benign. The acceptanceof this risk can prove to be fatal for the minority of cases where thelesion is malignant.

Finally, current vacuum assisted biopsy devices are not capable of beingused in conjunction with MRI. This is due to the fact that many of thecomponents are made of magnetic components that interfere with theoperation of the MRI. It would be desirable to perform biopsies inconjunction with MRI because it currently is the only non-invasivevisualization modality capable of defining the margins of the tumor.

In light of the foregoing disadvantages, a need remains for a tissueremoval device that reliably applies a vacuum without becoming pluggedwith blood and bodily fluids. A need also remains for a tissue removaldevice that is entirely disposable so that both exposure to bio-hazardand clean-up time are significantly minimized, while convenience ismaximized. A further need remains for a tissue removal device thatcompletely severs the maximum amount of tissue without requiringnumerous attempts at cutting the tissue. A need also remains for atissue removal device that is MRI compatible. Finally, a need remainsfor a biopsy tissue removal device that is completely automated,therefore making the handheld biopsy device a more efficient andattractive option.

SUMMARY OF THE INVENTION

The present invention fulfills the aforementioned needs by providing adisposable tissue removal device comprising a cutting element mounted toa handpiece. The cutting element includes an outer cannula defining atissue-receiving opening and an inner cannula concentrically disposedwithin the outer cannula.

The outer cannula has a trocar tip at its distal end and a cutting boardsnugly disposed within the outer cannula. The inner cannula defines aninner lumen that extends the length of the inner cannula, and whichprovides an avenue for aspiration. The inner cannula terminates in aninwardly beveled, razor-sharp cutting edge and is driven by, both arotory motor, and a reciprocating motor. As the inner cannula moves pastthe tissue-receiving opening, the inwardly beveled edge helps toeliminate the risk of catching the edge on the tissue-receiving opening.At the end of its stroke, the inner cannula makes contact with thecutting board to completely sever the tissue. The cutting board is madeof a material that is mechanically softer than the cutting edge yet hardenough to withstand the force of the inner cannula.

An aspiration is applied to the inner lumen through an aspiration tube.The aspiration tube communicates with a collection trap that isremovably mounted to the handpiece. The aspiration draws the sample intothe tissue-receiving opening and after the tissue is cut, draws thetissue through the inner cannula to a collection trap.

In a specific embodiment, both the rotary motor and the reciprocatingmotors are hydraulic motors. Because hydraulic motors do not require anyelectrical components, this feature allows all of the components to befabricated of MRI compatible materials.

In another embodiment, the tissue-receiving opening is formed byopposite longitudinal edges that form a number of teeth. The teeth faceaway from the cutting board at the distal end of the outer cannula. Theteeth help prevent the forward motion of the tissue in the opening asthe inner cannula moves forward toward the cutting board. This featuremaximizes the length and overall size of the core, ultimately resultingin a more efficient lesion removal.

In another embodiment, the outer cannula incorporates a stiffeningelement opposite the tissue-receiving opening. This stiffening elementaids in maintaining the longitudinal integrity of the outer cannula asit is advanced through the tissue.

In addition to the inwardly beveled edge of the inner cannula, oneembodiment incorporates additional features to prevent the inner cannulafrom rising up into the tissue-receiving opening. A bead of stiffeningmaterial may be affixed to the inner wall of the outer cannula, or adimple may be formed in the inner wall of the outer cannula. The bead,or dimple urges the inner cannula away from the tissue-receiving openingand prevents the inner cannula from catching on the opening.

DESCRIPTION OF THE FIGURES

FIG. 1 is a top perspective view of a tissue biopsy apparatus inaccordance with one embodiment of the present invention.

FIG. 2 is a top elevational view of the tissue biopsy apparatus shown inFIG. 1.

FIG. 3A and FIG. 3B are side cross-sectional views of the tissue biopsyapparatus depicted in FIGS. 1 and 2, with the tissue cutting innercannula shown in its retracted and extended positions.

FIG. 4 is a perspective view of a cover for the tissue biopsy apparatusas shown FIG. 1.

FIG. 5 is an enlarged side cross-sectional view of the operating end ofthe tissue biopsy apparatus depicted in FIGS. 1 and 2.

FIG. 6 is a side partial cross-sectional view of working end of a tissuebiopsy apparatus in accordance with an alternative embodiment.

FIG. 7 is an end cross-sectional view of the apparatus depicted in FIG.6, taken along lines 7-7 as viewed in the direction of the arrows.

FIG. 8 is an end cross-sectional view similar to FIG. 7 showing amodified configuration for a stiffening member.

FIG. 8(a) is an end cross-sectional view similar to FIG. 7 showing amodified configuration for another stiffening member.

FIG. 9 is an enlarged side cross-sectional view of a fluid introductionport at the hub connecting the outer cannula to the handpiece for atissue biopsy apparatus as depicted in FIG. 1.

FIG. 10 is a schematic drawing of the hydraulic control system for theoperation of the tissue biopsy apparatus shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended. The invention includes any alterationsand further modifications in the illustrated devices and describedmethods and further applications of the principles of the inventionwhich would normally occur to one skilled in the art to which theinvention relates.

A tissue biopsy apparatus 10 in accordance with one embodiment of thepresent invention is shown in FIGS. 1-5. The apparatus 10 includes acutting element 11 mounted to a handpiece 12. The cutting element 11 issized for introduction into a human body. Most particularly, the presentinvention concerns an apparatus for excising breast tissue samples.Thus, the cutting element 11 and the overall biopsy apparatus 10 areconfigured for ease of use in this surgical environment. In theillustrated embodiment, the biopsy apparatus 10 is configured as ahand-held device. However, the same inventive principles can be employedin a tissue biopsy apparatus that is used stereotatically in which theapparatus is mounted on a support fixture that is used to position thecutting element 11 relative to the tissue to be sampled. Nevertheless,for the purposes of understanding the present invention, the tissuebiopsy apparatus will be described as a hand-held device.

The cutting element 11 is configured as “tube-within-a-tube” cuttingdevice. More specifically, the cutting element 11 includes an outercannula 15 terminating in a tip 16. Preferably, the tip is a trocar tipthat can be used to penetrate the patient's skin. Alternatively, the tip16 can simply operate as a closure for the open end of the cannula 15.In this instance, a separate introducer would be required.

The cutting element 11 further includes an inner cannula 17 that fitsconcentrically within the outer lumen 27 (FIG. 5) of the outer cannula15. In the most preferred embodiment, both a rotary motor 20 (FIG. 1)and a reciprocating motor 22 drive the inner cannula 17. Both motors aresupported within the handpiece 12. Again, in accordance with thepreferred embodiment the rotary motor 20 and reciprocating motor 22 areconfigured for simultaneous operation to translate the inner cannula 17axially within the outer cannula 15, while rotating the inner cannula 17about its longitudinal axis.

One specific configuration of the working end of the cutting element 11is depicted in FIG. 5. The outer cannula 15 defines a tissue-receivingopening 25, which communicates with the outer lumen 27. A pair ofopposite longitudinal edges 26 (FIGS. 1 and 2) define thetissue-receiving opening 25. The outer cannula 15 is open at its distalend 28 with the trocar tip 16 engaged therein. Preferably, the trocartip 16 forms an engagement hub 30 that fits tightly within the distalend 28 of the outer cannula 15. The hub 30 can be secured by welding,press-fit, adhesive or other means suitable for a surgical biopsyinstrument.

The working end of the cutting element 11 further includes a cuffingboard 31 that is at least snugly disposed within the outer lumen 27 atthe distal end 28 of the outer cannula 15. Most preferably, the cuttingboard 31 is in direct contact with the engagement hub 30 of the trocartip 16. The cutting board 31 can be permanently affixed within the outercannula 15 and/or against the engagement hub 30 of the trocar tip.

The inner cannula 17 defines an inner lumen 34 that is hollow along theentire length of the cannula to provide for aspiration of the biopsysample. The inner cannula 17 terminates in a cutting edge 35. Preferablythe cutting edge 35 is formed by an inwardly beveled surface 36 toprovide a razor-sharp edge. The inwardly beveled surface helps eliminatethe risk of catching the edge 35 on the tissue-receiving opening 25 ofthe outer cannula. In addition, the beveled surface 36 helps avoidpinching the biopsy material between the inner and outer cannulas duringa cutting stroke.

In a specific embodiment, both the outer cannula 15 and the innercannula 17 are formed of a surgical grade metal. Most preferably, thetwo cannulae are formed of stainless steel. In the case of an MRIcompatible device, the cannulae can be formed of Inconel, Titanium orother materials with similar magnetic characteristics. Likewise, thetrocar tip 16 is most preferably formed of stainless steel honed to asharp tip. The trocar tip 16 can be suitably bounded to the outercannula 15, such as by welding or the use of an appropriate adhesive.

The cutting board 31 is formed of a material that is configured toreduce the friction between the cutting edge 35 of the inner cannula 17and the cutting board 31. The cutting edge 35 necessarily bears againstthe cutting board 31 when the inner cannula 17 is at the end of itsstroke while severing a tissue sample. Since the inner cannula is alsorotating, the cutting edge necessarily bears directly against thecutting board 31, particularly after the tissue sample has been cleanlysevered. In prior devices, the impact-cutting surface has been formed ofthe same material as the cutting element. This leads to significant wearor erosion of the cutting edge. When numerous cutting cycles are to beperformed, the constant wear on the cutting edge eventually renders itincapable of cleanly severing a tissue sample.

Thus, the present invention contemplates forming the cutting board 31 ofa material that reduces this frictional wear. In one embodiment, thecutting board 31 is formed of a material that is mechanically softerthan the material of the cutting edge 35. However, the cutting board 31cannot be so soft that the cutting edge 35 forms a pronounced circulargroove in the cutting board, which significantly reduces the cuttingefficiency of the inner cannula. In a most preferred embodiment of theinvention, the cutting board 31 is formed of a plastic material, such aspolycarbonate, ABS or DELRIN®.

Returning again to FIGS. 1, 2 and 3A-3B, the rotary motor 20 includes amotor housing 39 that is sized to reciprocate within the handpiece 12.The housing 39 defines a pilot port 40 that is connected to thehydraulic control system 150 (see FIG. 10) by appropriate tubing. Thepresent invention contemplates that the motor 20 can be a number ofhydraulically powered rotating components. Most preferably, the motor 20is an air motor driven by pressured air. Thus, the motor 20 includes avaned rotor 42 that is mounted on a hollow tubular axle 43 extendingthrough the motor housing 39. The axle 43 is supported on bearings 44 atopposite ends of the housing so that the rotor 42 freely rotates withinthe motor housing 39 under pneumatic pressure.

In the illustrated embodiment, tubular axle 43 is connected to theproximal end 37 of the inner cannula 17 by way of a coupler 46. The endsof the two tubes are mounted within the coupler 46 and held in place bycorresponding set screws 47. Preferably the coupler 46 is formed of aplastic material that provides a generally airtight seal around thejoint between the inner cannula 17 and the tubular axle 43. It isimportant that the coupler 46 provide a solid connection of the innercannula 17 to the rotating components of the motor 20 so that the innercannula 17 does not experience any torrential slip during the cuttingoperation.

Since the inner cannula 17 provides an avenue for aspiration of thebiopsy sample, the invention further contemplates an aspiration tube 50that mates with the tubular axle 43. Thus, the tissue aspiration pathfrom the working end of the cutting element 11 is along the inner lumen34 of the inner cannula 17, through the tubular axle 43 of the rotarymotor 20, and through the aspiration tube 50 to a tissue collectionlocation in the form of a collection trap 55. In order to maintain thevacuum or aspiration pressure within this aspiration path, theaspiration tube 50 must be fluidly sealed against the tubular axial 43.Thus, the motor housing 39 defines a mounting hub 51 into which theaspiration tube 50 is engaged. The position of the aspiration tube 50 isfixed by way of a setscrew 52 passing through the mounting hub 51. Incontrast to the joint between the inner cannula 17 and the tubular axial43, the joint between the aspiration tube 50 and the tubular axial 43allows relative rotational between the two components. The tubular axle43, of course, rotates with the rotor 42. However, the aspiration tube50 need not rotate for use with the biopsy apparatus of the presentinvention. The mounting hub 51 can include an arrangement of seal rings(not shown) at the joint between the aspiration tube 50 and the tubularaxle 43 to further seal the aspiration system.

The aspiration tube 50 communicates with a collection trap 55 that isremovably mounted to the handpiece 12. The collection trap 55 includes apilot port 107 that is connected by appropriate tubing to the hydrauliccontrol system 150, as described in more detail herein. For the presentpurposes, it is understood that a vacuum or aspiration pressure is drawnthrough the pilot port 107 and the collection trap 55. This vacuum thendraws a tissue sample excised at the working end of the cutting element11, all the way through the inner cannula 17, tubular axle 43 andaspiration tube 50 until it is deposited within the trap. Details of thecollection trap 55 will be discussed herein.

As explained above, the present invention contemplates an inner cannula17 that performs its cutting operation by both rotary and reciprocatingmotion. Thus, the handpiece 12 supports a reciprocating motor 22. In oneaspect of the invention, both motors 20 and 22 are hydraulicallypowered, most preferably pneumatically. This feature allows the motorsto be formed of plastic, since no electrical components are required. Infact, with the exception of the outer cannula 15, trocar tip 16 andinner cannula 17, every component of the biopsy apparatus 10 inaccordance with the present invention can be formed of a non-metallicmaterial, most preferably a medical grade plastic. Thus, the biopsyapparatus 10 is eminently compatible with surgical imaging systems thatmay be used during the biopsy procedure. The compatibility of theapparatus 10 with Magnetic Resonance Imaging (MRI) is important becauseMRI is currently the only non-invasive visualization modality capable ofdefining the margins of the tumor. In addition, since the biopsyapparatus is formed of a relatively inexpensive plastic (as opposed to amore expensive metal), the entire apparatus can be disposable. Moreover,the elimination of substantially all metal components reduces theoverall weight of the handpiece 12, making it very easily manipulated bythe surgeon.

Referring most specifically to FIGS. 3A and 3B, the reciprocating motor22 includes a pneumatic cylinder 60. The cylinder 60 includes a pilotport 61 that connects the cylinder to the hydraulic control system 150through appropriate tubing. The motor 22 includes a piston 63 thatreciprocates within the cylinder 60 in response to hydraulic fluidpressure provided at the pilot port 61. The piston 63 includes a centralbore 64 for mounting the piston 63 to the aspiration tube 50. In oneembodiment, the aspiration tube 50 is press-fit within the bore 64. Theengagement between the aspiration tube 50 and the piston 63 can beenhanced by use of a set screw (not shown) or an adhesive or epoxy. Atany rate, it is essential that the aspiration tube 50 and piston 63 movetogether, since the motor 22 must eventually drive the inner cannula 17axially within the outer cannula.

It should be understood that in addition to powering the inner cannula,the piston 63 also reciprocates the rotary motor 20, which isessentially mounted to the reciprocating aspiration conduit. Thismovement is depicted by comparing the position of the rotary motor 20between FIG. 3A and FIG. 3B. More specifically, the motor 20 as well asthe aspiration conduit, including the inner cannula 17, moves within thehandpiece 12. Preferably, the handpiece housing 70 is provided withopenings 73 (FIG. 3B) at its opposite ends for slidably supporting theaspiration tube 50 and inner cannula 17. Since the distal housing 70 ispreferably formed of a plastic material, no thrust bearings or rotarybearings are necessary to accommodate low friction axial movement of thecannula through the housing openings 73.

The biopsy apparatus 10 includes a handpiece 12 that carries all of theoperating components and supports the outer and inner cannulas. Thehandpiece 12 includes a distal housing 70 within which is disposed therotary motor 20. The distal end 71 of the housing 70 is configured intoa fitting 72. This fitting 72 engages a mating flange 77 on an outercannula hub 75. The hub 75 supports the outer cannula 15 within anengagement bore 76 (see FIG. 3B).

In accordance with one aspect of the present invention, the engagementbetween the outer cannula hub 75 and the distal end 71 of the housing 70need not be airtight. In other words, the mating components of thefitting between the two parts need not be capable of generating afluid-tight seal. In accordance with one embodiment of the invention,the engagement between the hub 75 and the housing 70 for supporting theouter cannula 15 provides a leak path through the outer lumen 27 to theatmosphere. In the use of the tissue biopsy apparatus 10, providingaspiration through the inner lumen 34 of the inner cutting cannula 17will draw tissue through the inner lumen. As the tissue advances fartheralong the lumen, in some instances a vacuum can be created behind theadvancing tissue. At some point in these instances, the tissue will stopadvancing along the length of the inner lumen because the vacuum behindthe tissue sample equals the vacuum in front of the tissue sample thatis attempting to draw the sample to the collection trap 55. Thus, theleak path through the outer lumen 27 allows atmospheric air to fall inbehind the tissue sample when the inner cutter is retracted from thecutting board. The atmospheric air helps to relieve the vacuum behindthe advancing tissue and aids in drawing the tissue down the length ofthe aspiration channel to the collection trap 55. However, in someapplications, particularly where smaller “bites” of the target tissueare taken, the atmospheric air leak path is not essential.

Preferably the fitting 72 and the mating flange 77 can be engaged bysimple twisting motion, most preferably via Luer-type fittings. In use,the cannula hub 75 is mounted on the handpiece 12, thereby supportingthe outer cannula 15. The handpiece can then be used to project theouter cannula into the body adjacent the sample site. In certain uses ofthe biopsy apparatus 10, it is desirable to remove the handpiece 12 fromthe cannula hub 75 leaving the outer cannula 15 within the patient. Forexample, the outer cannula 15 can be used to introduce an anesthetic. Inother applications, once the target tissue has been completely excised,the outer cannula can be used to guide a radio-opaque marker to mark thelocation the removed material.

Returning again to the description of the housing 70, the housingdefines an inner cavity 79 that is open through an access opening 81.The access opening 81 is preferably provided to facilitate assembly ofthe tissue biopsy apparatus 10. The distal end 71 of the housing 70 canbe provided with a pair of braces 81 that add stiffness to the distalend 71 while the apparatus is in use. The braces 80 allow the distalhousing 70 to be formed as a thin-walled plastic housing. Similar bracescan be provided at the opposite end of the distal housing as necessaryto add stiffness to the housing.

The distal housing is configured to support the reciprocating motor 22and in particular the cylinder 60. Thus, in one embodiment of theinvention, the proximal end 83 of the distal housing 70 defines apressure fitting 84. It is understood that this pressure fitting 84provides a tight leak-proof engagement between the distal end 88 of thecylinder 60 and the proximal end 83 of the housing. In one specificembodiment, the pressure fitting 84 forms a spring cavity 85 withinwhich a portion of the return spring 66 rests. In addition, in aspecific embodiment, the pressure fitting 84 defines distal piston stop86. The piston 63 contacts these stops at the end of its stroke. Thelocation of the piston stop 86 is calibrated to allow the cutting edge35 to contact the cutting board 31 at the working end of the cuttingelement 11 to allow the cutting edge to cleanly sever the biopsy tissue.

In the illustrated embodiment, the cylinder 60 is initially provided inthe form of an open-ended cup. The open end, corresponding to distal end88, fastens to the pressure fitting 84. In specific embodiments, thepressure fitting can include a threaded engagement, a press-fit or anadhesive arrangement.

The cylinder cup thus includes a closed proximal end 89. This proximalend defines the pilot port 61, as well as a central opening 62 (FIG. 3B)through which the aspiration tube 50 extends. Preferably, the proximalend 89 of the cylinder 60 is configured to provide a substantiallyairtight seal against the aspiration tube 50 even as it reciprocateswithin the cylinder due to movement of the piston 63. The proximal end89 of the cylinder 60 defines a proximal piston stop 90, which caneither be adjacent the outer cylinder walls or at the center portion ofthe proximal end. This proximal piston stop 90 limits the reverse travelof the piston 63 under action of the return spring 66 when pressurewithin the cylinder has been reduced.

In a further aspect of the invention, the collection trap 55 is mountedto the handpiece 12 by way of a support housing 93. It should beunderstood that in certain embodiments, the handpiece 12 can be limitedto the previously described components. In this instance, the collectiontrap 55 can be situated separate and apart from the handpiece,preferably close to the source of vacuum or aspiration pressure. In thiscase, the proximal end of the aspiration tube 50 would be connected tothe collection trap by a length of tubing. In the absence of thecollection trap 55, the aspiration tube 50 would reciprocate away fromand toward the proximal end of the cylinder 60, so that it is preferablethat the handpiece includes a cover configured to conceals thereciprocating end of the aspiration tube.

However, in accordance with the most preferred embodiment, thecollection trap 55 is removably mounted to the handpiece 12. A pair oflongitudinally extending arms 94, that define an access opening 95therebetween, forms the support housing 93. The support housing 93includes a distal end fitting 96 that engages the proximal end 89 ofcylinder 60. A variety of engagements are contemplated, preferably inwhich the connection between the two components is generally airtight.The proximal end 97 of the support housing 93 forms a cylindricalmounting hub 98. As best shown in FIG. 1, the mounting hub 98 surroundsa proximal end of the collection trap 55. The hub forms a bayonet-typemounting groove 99 that receives pins 103 attached to the housing 102 ofthe trap 55. A pair of diametrically opposite wings 104 can be providedon the housing 102 to facilitate the twisting motion needed to engagethe bayonet mount between the collection trap 55 and the support housing93. While the preferred embodiment contemplates a bayonet mount, otherarrangements for removably connecting the collection trap 55 to thesupport housing 93 are contemplated. To be consistent with one of thefeatures of the invention, it is preferable that this engagementmechanism be capable of being formed in plastic.

In order to accommodate the reciprocating aspiration tube, the supporthousing 93 is provided with an aspiration passageway 100 that spansbetween the proximal and distal ends of the housing. Since theaspiration tube 50 reciprocates, it preferably does not extend into thecollection trap 55. As excised tissue is drawn into the trap 55, areciprocating aspiration tube 50 can contact the biopsy materialretained within the trap. This movement of the tube can force tissueinto the end of the tube, clogging the tube. Moreover, the reciprocationof the aspiration tube can compress tissue into the end of the trap,thereby halting the aspiration function.

The collection trap 55 includes a housing 102, as previously explained.The housing forms a pilot port 107, which is connectable to a vacuumgenerator. Preferably in accordance with the present invention,appropriate tubing to the hydraulic control system 150 connects thepilot port 107. The trap 55 includes a filter element 110 mounted withinthe trap. In the preferred embodiment, the filter element is a meshfilter than allows ready passage of air, blood and other fluids, whileretaining excised biopsy tissue samples, and even morcellized tissue. Inaddition, the filter element 110 is preferably constructed so thatvacuum or aspiration pressure can be drawn not only at the bottom end ofthe filter element, but also circumferencially around at least aproximal portion of the element 110. In this way, even as material isdrawn toward the proximal end of the filter, a vacuum can still be drawnthrough other portions of the filter, thereby maintaining the aspirationcircuit.

The handpiece 12 can include individual covers for closing the accessopening 81 in the distal housing 70 and the access openings 95 in thesupport housing 93. Those covers can support tubing for engagement withthe pilot ports 40 and 61. Alternatively and most preferably, a singlecover 13 as depicted in FIG. 4, is provided for completely enclosing theentire handpiece. The distal end 71 of the housing 70 can define anumber of engagement notches 115 equally spaced around the perimeter ofthe distal end. The handpiece cover 13 can then include a like number ofequally distributed tangs 117 projecting inwardly from the inner surfacefrom the 118. These tangs are adapted to snap into the engagementnotches 115 to hold the cover 113 in position over the handpiece 12. Thecover can be attached by sliding axially over the handpiece 12. Thecover 13 can include fittings for fluid engagement with the two pilotports 40 and 61. Alternatively, the cover can be formed with openingsfor insertion of engagement tubing to mate with the respective pilotports to provide hydraulic fluid to the rotary motor 20 and thereciprocating motor 22. In a specific embodiment, the cover 13 extendsfrom the distal end 71 of the distal housing 70 to the proximal end 97of the support housing 93. The cover can thus terminate short of thebayonet mounting feature between the support housing and the collectiontrap 55. Although not shown in the figures, the proximal end 97 of thesupport housing 93 can be configured to include a similar array ofengagement notches with a corresponding array of mating tangs formed atthe proximal end of the cover 13.

Referring now to FIGS. 6-8, alternative embodiments of the outer cannulaare depicted. As shown in FIG. 6 an outer cannula 125 includes atissue-receiving opening 126. The opening is formed by oppositelongitudinal edges 127. In one specific embodiment, a number of teeth129 are formed at each longitudinal edge 127. As depicted in the figure,the teeth are proximally facing—i.e., away from the cutting board 31(not shown) at the distal end of the outer cannula. With thisorientation, the teeth 129 help prevent forward motion of tissue drawninto the opening 126 as the inner cannula 17 moves forward toward thecutting board. In prior devices, as the reciprocating cutting elementadvances through the outer cannula, the cutting edge not only starts tosever the tissue, it also pushes tissue in front of the inner cannula.Thus, with these prior devices, the ultimate length of the biopsy sampleretrieved with the cut is smaller than the amount of tissue drawn intothe tissue-receiving opening of the outer cannula. With the teeth 129 ofthe outer cannula 125 of this embodiment of the invention, the tissuesample removed through the inner cannula 17 is substantially the samelength as the tissue-receiving opening 126. As the inner cannula 17advances into the tissue, each of the teeth 129 tends to hold the tissuein place as the cutting edge 35 severs the tissue adjacent the outercannula wall. With this feature, each “bite” is substantially as largeas possible so that a large tissue mass can be removed with much fewer“bites” and in a shorter period of time. In addition to supporting thesubject tissue as the inner cannula advances, the teeth can also cutinto the tissue to prevent it from retracting out of the opening as theinner cutting cannula 17 advances.

The outer cannula 125 depicted in FIG. 6 can also incorporate astiffening element 131 opposite the tissue-receiving opening 126. Thestiffening element 131 adds bending stiffness to the outer cannula 125at the distal end in order to maintain the longitudinal integrity of theouter cannula 125 as it is advanced into a tissue mass. In some priordevices that lack such a stiffening element, the working end of thecutting device is compromised as it bends slightly upward or downward asthe outer cannula passes into the body. This bending can either close orexpand the tissue-receiving opening, which leads to difficulties inexcising and retrieving a tissue sample. The cutting mechanism of thepresent invention relies upon full, flush contact between the cuttingedge of the inner cannula 17 and the cutting board 31. If the end of theouter cannula 125 is slightly askew, this contact cannot be maintained,resulting in an incomplete slice of the tissue sample.

As depicted in the cross-sectional view of the FIG. 7, the stiffeningelement 131 in one embodiment is a crimp extending longitudinally in theouter wall of the cannula substantially coincident with thetissue-receiving opening 126. The outer cannula 125′ depicted in FIG. 8shows two additional versions of a stiffening element. In both cases, abead of stiffening material is affixed to the outer cannula. Thus in onespecific embodiment, a bead 131′ is adhered to the inner wall of theouter cannula. In a second specific embodiment, a bead 131″ is affixedto the outside of the outer cannula. In either case, the beads can beformed of a like material with the outer cannula, and in both cases, thebeads provide the requisite additional bending stiffness. Anotherversion of a stiffening element is shown if FIG. 8(a). In this case, alayer 131′″ of additional stainless steel is bonded to the outer wall ofthe outer cannula 125″.

Returning to FIG. 6, a further feature that can be integrated into theouter cannula 125 is the dimple 135. One problem frequently experiencedby tube-within-a-tube cutters is that the inner reciprocating cutterblade contacts or catches on the outer cannula at the distal edge of thetissue-receiving opening. With the present invention, the dimple 135urges the inner cannula 17 away from the tissue-receiving opening 126.In this way, the dimple prevents the cutting edge of the inner cannula17 from catching on the outer cannula as it traverses thetissue-receiving opening. In the illustrated embodiment of FIG. 6, thedimple 135 is in the form of a slight crimp in the outer cannula 125.Alternatively, as with the different embodiments of the stiffeningelement, the dimple 135 can be formed by a protrusion affixed or adheredto the inner surface of the outer cannula. Preferably, the dimple 135 issituated immediately proximal to the tissue-receiving opening to helpmaintain the distance between the cutting edge and the tissue-receivingopening.

As previously described, the outer cannula 15 is supported by a hub 75mounted to the distal end of the handpiece. In an alternative embodimentdepicted in FIG. 9, the outer cannula hub 140 provides a mean forintroducing fluids into the outer lumen 27 of the outer cannula. Thus,the hub 140 includes an engagement bore 141 within which the outercannula 15 is engaged. The hub also defines a flange 142 configured formating with the fitting 72 at the distal end 71 of the housing 70. Thus,the outer cannula hub 140 is similar to the hub 75 described above. Withthis embodiment, however, an irrigation fitting 145 is provided. Thefitting defines an irrigation lumen 146 that communicates with theengagement bore 141.

Ultimately, this irrigation lumen is in fluid communication with theouter lumen 27 of the outer cannula 15. The irrigation fitting 145 canbe configured for engagement with a fluid-providing device, such as asyringe. The hub 140 thus provides a mechanism for introducing specificfluids to the biopsy site. In certain procedures, it may be necessary tointroduce additional anesthetic to the sampling site, which can bereadily accommodated by the irrigation fitting 145.

As discussed above, the preferred embodiment of the tissue biopsyapparatus 10 according to the present invention relies upon hydraulicsor pneumatics for the cutting action. Specifically, the apparatusincludes a hydraulic rotary motor 20 and a hydraulic reciprocating motor22. While the apparatus 10 can be adapted for taking a single biopsyslice, the preferred use is to completely remove a tissue mass throughsuccessive cutting slices. In one typical procedure, the cutting element11 is positioned directly beneath a tissue mass, while an imaging deviceis disposed above the mass. The imaging device, such as an ultra-soundimager, provides a real-time view of the tissue mass as the tissuebiopsy apparatus 10 operates to successively remove slices of the mass.Tissue is continuously being drawn into the cutting element 11 by theaspiration pressure or vacuum drawn through the inner cannula 17.Successive reciprocation of the inner cannula 17 removes large slices ofthe mass until it is completely eliminated.

In order to achieve this continuous cutting feature, the presentinvention contemplates a hydraulic control system 150, as illustrated inthe diagram of FIG. 10. Preferably the bulk of the control system ishoused within a central console. The console is connected to apressurized fluid source 152. Preferably the fluid source provides aregulated supply of filtered air to the control system 150.

As depicted in this diagram of FIG. 10, pressurized fluid from thesource as provided at the several locations 152 throughout the controlsystem. More specifically, pressurized fluid is provided to five valvesthat form the basis of the control system.

At the left center of the diagram of FIG. 10, pressurized fluid 152passes through a pressure regulator 154 and gauge 155. The gauge 155 ispreferably mounted on the console for viewing by the surgeon or medicaltechnician. The pressure regulator 154 is manually adjustable to controlthe pressurized fluid provided from the source 152 to the two-positionhydraulic valve 158. The valve 158 can be shifted between a flow path158 a and a flow path 158 b. A return spring 159 biases the hydraulicvalve to its normal position 158 a.

In the normally biased position of flow path 158 a, the valve 158connects cylinder pressure line 161 to the fluid source 152. Thispressure line 161 passes through an adjustable flow control valve 162that can be used to adjust the fluid flow rate through the pressure line161. Like the pressure gauge 155 and pressure regulator 154, theadjustable flow control valve 162 can be mounted on a console formanipulation during the surgical procedure.

The pressure line 161 is connected to the pilot port 61 of thereciprocating motor 22. Thus, in the normal or initial position of thehydraulic control system 150, fluid pressure is provided to the cylinder60 to drive the piston 63 against the biasing force of the return spring66. More specifically with reference to FIG. 3B, the initial position ofthe hydraulic valve 158 is such that the reciprocating motor and innercannula are driven toward the distal end of the cutting element. In thisconfiguration, the inner cannula 17 covers the tissue-receiving opening25 of the outer cannula 15. With the inner cannula so positioned, theouter cannula can be introduced into the patient without risk of tissuefilling the tissue-receiving opening 25 prematurely.

Pressurized fluid along cylinder pressure 161 is also fed to a pressureswitch 165. The pressure switch has two positions providing flow paths165 a and 165 b. In addition, an adjustable return spring 166 biasesthis switch to its normal position at which fluid from the pressuresource 152 terminates within the valve. However, when pressurized fluidis provided through cylinder pressure line 161, the pressure switch 165moves to its flow path 165 b in which the fluid source 152 ishydraulically connected to the pressure input line 168. This pressureinput line 168 feeds an oscillating hydraulic valve 170. It is thisvalve that principally operates to oscillate the reciprocating motor 22by alternately pressurizing and releasing the two-position hydraulicvalve 158. The pressure switch 165 is calibrated to sense an increase inpressure within the cylinder pressure line 161 or in the reciprocatingmotor cylinder 60 that occurs when the piston 66 has reached the end ofits stroke. More specifically, the piston reaches the end of its strokewhen the inner cannula 17 contacts the cutting board 31. At this point,the hydraulic pressure behind the piston increases, which increase issensed by the pressure valve 165 to stroke the valve to the flow path165 b.

The oscillating hydraulic valve 170 has two positions providing flowpaths 170 a and 170 b. In position 170 a, input line 179 is fed tooscillating pressure output line 172. With flow path 170 b, the inputline 179 is fed to a blocked line 171. Thus, with fluid pressureprovided from pressure switch 165 (through flow path 165 b), theoscillating valve 170 opens flow path 170 a which completes a fluidcircuit along output line 172 to the input of the hydraulic valve 158.

Fluid pressure to output line 172 occurs only when there is fluidpressure within input line 179. This input line is fed by valve 176,which is operated by foot pedal 175. The valve 176 is biased by a returnspring 177 to the initial position of flow path 176 a. However, when thefoot pedal 175 is depressed, the valve 176 is moved against the force ofthe spring to flow path 176 b. In this position, pressurized fluid fromthe source 152 is connected to the foot pedal input line 179. When theoscillating hydraulic valve 170 is in its initial position flow path 170a, pressurized fluid then flows through input line 179 to output line172 and ultimately to the hydraulic valve 158.

The fluid pressure in the output line 172 shifts the valve 158 to theflow path 158 b. In this position, the fluid pressure behind the piston63 is relieved so that the return spring 66 forces the piston toward theproximal end. More specifically, the return spring retracts the innercannula 17 from the tissue cutting opening 25. The relief of the fluidpressure in line 161 also causes the pressure switch 165 to return toits initial neutral position of flow path 165 a, due to the action ofthe return spring 166. In turn, with the flow path 165 a, the pressureinput line 168 is no longer connected to the fluid source 152, so nopressurized fluid is provided to the oscillating hydraulic valve 170.Since this valve is not spring biased to any particular state, itsposition does not necessarily change, except under conditions describedherein.

Returning to the foot pedal 175 and valve 176, once the foot pedal isreleased, the biasing spring 177 forces the valve 176 from its flow path176 b to its normal initial flow path 176 a. In this position the footpedal input line 179 is no longer connected to the fluid source 152.When the oscillating valve 170 is at flow path 170 a, the fluid pressurethrough output line 172 is eliminated. In response to this reduction influid pressure, hydraulic valve 158 is shifted to its original flow path158 a by operation of the return spring 159. In this position, thecylinder pressure line 161 is again connected to the fluid source 152,which causes the reciprocating motor 22 to extend the inner cannula 17to its position blocking the tissue-receiving opening 25. Thus, inaccordance with the present invention, the hydraulic control system 150starts and finishes the tissue biopsy apparatus 10 with thetissue-receiving opening closed. It is important to have the openingclosed once the procedure is complete so that no additional tissue maybe trapped or pinched within the cutting element 11 as the apparatus isremoved from the patient.

Thus far the portion of the hydraulic control system 150 that controlsthe operation of the reciprocating motor 22 has been described. Thesystem 150 also controls the operation of the rotary motor 20. Again, inthe most preferred embodiment, the motor 20 is an air motor. This airmotor is controlled by another hydraulic valve 182. As shown in FIG. 10,the initial position of the valve provides a flow path 182 a in whichthe fluid source 152 is connected to blocked line 183. However, when thehydraulic valve 182 is pressurized, it moves to flow path 182 b in whichthe fluid source 152 is connected to the pilot port 140 of the airmotor. In this position, pressurized fluid continuously drives the airmotor 20, thereby rotating the inner cannula 17. It can be notedparathentically that a muffler M can be provided on the air motor toreduce noise.

The rotary motor hydraulic valve 182 is controlled by fluid pressure onpressure activation line 180. This activation line 180 branches from thefoot pedal input line 179 and is connected to the foot pedal switch 176.When the foot pedal 175 is depressed, the switch moves to its flow path176 b. In this position the pressure activation line 180 is connected tothe fluid source 152 so fluid pressure is provided directly to therotary motor hydraulic valve 182. As with the other hydraulic valves,the valve 182 includes a biasing spring 184 that must be overcome by thefluid pressure at the input to the valve.

It should be understood that since the fluid control for the rotarymotor 20 is not fed through the oscillating hydraulic valve 170, themotor operates continuously as long as the foot pedal 175 is depressed.In addition, it should also be apparent that the speed of the rotarymotor 20 is not adjustable in the illustrated embodiment. Since themotor 20 is connected directly to the fluid source 152, which ispreferably regulated at a fixed pressure, the air motor actuallyoperates at one speed. On the other hand, as discussed above, thereciprocating motor 22 is supplied through a pressure regulator 154 anda flow control valve 162. Thus, the speed of reciprocation of thecutting blade 35 is subject to control by the surgeon or medicaltechnician. The reciprocation of the cutting element 11 can be afunction of the tissue being sampled, the size of the tissue biopsysample to be taken, and other factors specific to the particularpatient. These same factors generally do not affect the slicingcharacteristic of the cutting edge 35 achieved by rotating the innercannula.

The hydraulic control system 150 also regulates the aspiration pressureor vacuum applied through the aspiration conduit, which includes theinner cannula 17. In the illustrated embodiment, the pressure activationline 180 branches to feed an aspiration valve 185. The valve is movablefrom its initial flow path 185 a to a second flow path 185 b. In theinitial flow path, the fluid source 152 is connected to a blocked line186. However, when fluid pressure is applied on line 180, the valve 185shifts against the biasing spring 187 to the flow path 185 b. In thispath, the venturi element 190 is connected to the fluid source. Thisventuri element thus generates a vacuum in a vacuum control line 193 andin aspiration line 191. Again, as with the air motor, the venturielement 190 can include a muffler M to reduce noise within thehandpiece.

As long as the foot pedal 175 is depressed and the valve 176 is in itsflow path 176 b, fluid pressure is continuously applied to theaspiration hydraulic valve 195 and the venturi element 190 generates acontinuous vacuum or negative aspiration pressure. As with the operationof the rotary motor, this vacuum is not regulated in the most preferredembodiment. However, the vacuum pressure can be calibrated by aselection of an appropriate venturi component 190.

When the venturi component 190 is operating, the vacuum drawn on controlline 193 operates on vacuum switch 194. A variable biasing spring 195initially maintains the vacuum switch 194 at its flow path 194 a. Inthis flow path, the vacuum input line 196 is not connected to any otherline. However, at a predetermined vacuum in control line 193, the valvemoves to flow path 194 b. In this position, the vacuum input line 196 isconnected to pressure line 192. In the preferred embodiment, the vacuumswitch 194 operates in the form of a “go-nogo” switch—in other words,when the aspiration vacuum reaches a predetermined operating threshold,the vacuum switch is activated. When the vacuum switch 184 is initiallyactivated, it remains activated as long as the foot pedal is depressed.Thus vacuum input line 196 is continuously connected to pressure line192 as long as the foot pedal 175 is depressed.

Looking back to the hydraulic valve 158, the fluid pressure in line 192,and ultimately in vacuum input line 196, is determined by the state ofvalve 158. When the valve 158 is in its flow path 158 a in whichregulated fluid pressure is provided to the reciprocating motor 22, thepressure line 192 is dead. However, when the valve 158 moves to flowpath 158 b, pressure line 192 is connected to the regulated fluidsource. Pressurized fluid then flows from pressure line 192, throughvacuum switch flow path 194 b, through vacuum input line 196 to the leftside of oscillating valve 170, causing the valve to stroke to flow path170 b. When the oscillating valve 170 is in this flow path, output line172 is dead, which allows valve 158 to move to its flow path 158 a underthe effect of the return spring 159. In this state, valve 158 allowspressurized fluid to again flow to the reciprocating motor 22 causing itto move through the next cutting stroke.

Thus, when both the valve 158 and the vacuum switch 194 are moved totheir alternate states, pressurized fluid passes from line 192, throughvacuum input line 196, and through an adjustable flow control valve 197to a second input for the oscillating hydraulic valve 170. Pressure onthe vacuum input line 196 shifts the oscillating valve 170 to its secondposition for flow path 170 b. In this position, pressurized fluidpassing through the foot pedal valve 176 terminates within valve 170. Asa consequence, the pressure in output line 172 drops which allows thehydraulic valve 158 shift back to its original position 158 a underoperation of the return spring 159. In this position, fluid pressure isagain supplied to the reciprocating motor 22 to cause the piston 66 tomove through its cutting stroke.

It should be appreciated that the oscillating valve 170 is influenced byfluid pressure on lines 168 and 196, and that these lines will not befully pressurized at the same time. When the system is initiallyenergized, pressure from source 152 is automatically supplied toreciprocating motor 22 and pressure valve 165, causing the valve to moveto flow path 165 b. In this state, line 168 is pressurized which shiftsoscillating valve 170 to the left to state 170 a. The oscillating valvewill remain in that state until line 196 is pressurized, regardless ofthe position of pressure switch 165. It can also be appreciated that inthe preferred embodiment, the fluid pressure on line 196 does notincrease to operating levels until the foot pedal 175 has been depressedand the aspiration circuit has reached its operating vacuum.

In an alternative embodiment, the vacuum switch 194 can be calibrated tosense fine changes in vacuum. In this alternative embodiment, thecompletion of this return stroke can be determined by the state of thevacuum switch 194. The vacuum switch 194 can operate as an indicatorthat a tissue sample has been drawn completely through the aspirationconduit into the collection trap 55. More specifically, when the vacuumsensed by vacuum switch 194 has one value when the inner cannula is opento atmospheric pressure. This vacuum pressure changes when a tissuesample is drawn into the inner cannula 17. The vacuum pressure changesagain when the tissue is dislodged so that the inner cannula is againopen to atmospheric pressure. At this point, the inner cannula 17 isclear and free to resume a cutting stroke to excise another tissuesample. Thus, the vacuum switch 194 can stroke to its flow path 194 b toprovide fluid pressure to the left side of the oscillating valve 170,causing the valve to stroke to flow path 170 b.

It can be appreciated from this detail explanation that the hydrauliccontrol system 150 provides a complete system for continuouslyreciprocating the axial motor 22. In addition, the system providesconstant continuous pressure to both the rotary motor 20 and theaspiration line 191, so long as the foot pedal 175 is depressed. Oncethe foot pedal is released, fluid pressure in activation line 180 dropswhich causes the air motor control valve 182 and the aspiration controlvalve 185 to shift to their original or normal positions in which fluidpressure is terminated to those respective components. However, in thepreferred embodiment, pressure is maintained to the reciprocating motor22 because the motor is fed through valve 158, which is connecteddirectly to the fluid source 152.

The hydraulic control system 150 in the illustrated embodimentincorporates five controllable elements. First, the fluid pressureprovided to activate the reciprocating motor 22 is controlled throughthe regulator 154. In addition, the fluid flow rate to the piston 66 iscontrolled via the adjustable control valve 162. The pressure at whichthe pressure switch 165 is activated is determined by an adjustablereturn spring 166. Likewise, the aspiration pressure vacuum at which thevacuum switch 194 is activated is controlled by an adjustable returnspring 195. Finally the adjustable flow control valve 197 controls thefluid flow from the vacuum switch 194 to the oscillating hydraulic valve170. Each of these adjustable elements controls the rate and duration ofoscillation of the reciprocating motor 22.

In the preferred embodiment, the pressure switch 165 essentiallyoperates as an “end of stroke” indicators. In other words, when theinner cannula 17 reaches the end of its forward or cutting stroke, itcontacts the cutting board 31. When it contacts the cutting board, thepressure in the cylinder pressure line 161 changes dramatically. It isthis change that causes the pressure switch 165 to change states. Thisstate change causes the oscillating valve 170 to shift valve 158 toterminate fluid pressure to the motor 22, causing it to stop its cuttingstroke and commence its return stroke.

During this return stroke, the excised tissue sample is gradually drawnalong the aspiration conduit. Also during the return stroke, fluidpressure bleeds from pressure line 161 and pressure switch 165 andultimately from line 168 feeding oscillating valve 170. When this valvestrokes, fluid pressure bleeds from valve 158 allowing the valve toreturn to state 158 a to pressurize the motor 22 for a new cuttingstroke. The operation of each of these hydraulic valves introduces aninherent time delay so that by the time the pressure to thereciprocating motor 22 has been restored the aspiration vacuum haspulled the tissue sample through the entire aspiration conduit and intothe collection trap 55.

The use of a hydraulically controlled inner cutting cannula providessignificant advantages over prior tissue cutting devices. The use ofhydraulics allows most of the operating components to be formed ofinexpensive and light-weight non-metallic materials, such asmedical-grade plastics. The hydraulic system of the present inventioneliminates the need for electrical components, which means thatelectrical insulation is unnecessary to protect the patient.

Perhaps most significantly, the hydraulically controlled reciprocationof the inner cutting cannula provides a cleaner and better-controlledcut of biopsy tissue. Since the reciprocating motor 22 is fed from asubstantially constant source of pressurized fluid, the pressure behindthe motor piston 63 remains substantially constant throughout thecutting stroke. This substantially constant pressure allows the innercutting cannula to advance through the biopsy tissue at a ratedetermined by the tissue itself.

In other words, when the cutting edge 35 encounters harder tissue duringa cutting stroke, the rate of advancement of the motor piston 63 andtherefor the inner cannula 17 decreases proportionately. This featureallows the cutting edge to slice cleanly through the tissue without therisk of simply pushing the tissue. The rotation of the cutting edge canfacilitate this slicing action. When the inner cannula encounters lessdense tissue, the constant pressure behind the piston 63 allows thecutting edge to advance more quickly through the tissue.

In alternative embodiment, the rotary motor 20 can consist of anelectric motor, rather than a pneumatic motor. As depicted in FIG. 11,the pressure activation line 180 can be fed to an on-off pressure switch198 that is governed by an adjustable bias spring 199. When theactivation line 180 is pressurized the switch 198 establishes aconnection between an electric reciprocating motor 20 and a battery pack200. Preferably, the battery pack 200 is mounted within the handpiece12, but can instead be wired to an external battery contained within theconsole.

In the preferred embodiment, the tissue biopsy apparatus 10 depicted inFIG. 1 has an overall length of under sixteen inches (16″) and an outerdiameter less than one and one quarter inches (1.25″). The outer cannulaand therefore the cutting element 11 have a length measured from thehandpiece 12 of approximately five inches (5″). The outer cannulapreferably has a nominal outer diameter of 0.148″ and a nominal innerdiameter of 0.136″. The inner cannula most preferably has a nominalouter diameter of 0.126″ so that it can reciprocate freely within theouter cannula without catching on the tissue cutting opening. The innercannula has a nominal wall thickness of 0.010″, which yields a nominalinner lumen diameter of about 0.106.″

The length of the tissue-receiving opening determines the length ofbiopsy sample extracted per each oscillation of the reciprocating motor22. In one specific embodiment, the opening has a length of about 0.7″,which means that a 0.7″ long tissue sample can be extracted with eachcutting cycle. In order to accommodate a large number of these biopsytissue slugs, the collection trap can have a length of about 2.5″ and adiameter of about 0.05″. Of course, the interior volume of thecollection trap can vary depending upon the size of each biopsy slug andthe amount of material to be collected. In a specific embodiment, thefilter disposed within the collection trap 55 manufactured byPerformance Systematix, Inc. of Callondoni, Mich.

In accordance with a specific embodiment, the cutting stroke for theinner cannula is about 0.905″. The return spring 66 within thereciprocating motor 22 is preferably a conical spring to reduce thecompressed height of the spring, thereby allow a reduction in theoverall length of the hydraulic cylinder 60. In addition, the returnspring 66 can be calibrated so that the return stroke occurs in lessthan about 0.3 seconds. Preferably, the inwardly beveled surface 36 ofcutting edge 35 is oriented at an approximately 30° angle.

The aspiration pressure vacuum is nominally set at 27 in.Hg. during thecutting stroke. When the cannula is retracted and the outer lumen 27 isopen, the vacuum pressure is reduced to 25 in.Hg. This aspirationpressure normally allows aspiration of a tissue sample in less thanabout 1 second and in most cases in about 0.3 second. In accordance witha most preferred embodiment, the hydraulic control system 150 preferablyis calibrated so that the inner cannula dwells at its retracted positionfor about 0.3 seconds to allow complete aspiration of the tissue sample.Adjusting the return spring 195 of the vacuum switch 194 can controlthis dwell rate.

In a preferred embodiment, the inner cannula 17 can advance through thecutting stroke in about two seconds. This stroke speed can beaccomplished with a regulated pressure at source 152 of about 20 p.s.i.When the inner cannula reaches the end of its cutting stroke, thepressure can increase at about five p.s.i. per second. Preferably, thereturn spring 166 of the pressure switch 165 is set so that the end ofcutting stroke is sensed within about 0.5 seconds.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character. It should be understoodthat only the preferred embodiments have been shown and described andthat all changes and modifications that come within the spirit of theinvention are desired to be protected.

EXAMPLES Example 1

Eighteen trial biopsies were performed upon patients after obtaininginformed consent and preparing the patients according to standard biopsyprocedures. In each case, biopsies were performed according to thefollowing procedure. The patient was positioned on her back on thesurgical table, and the lesion was located using ultrasound. A smallincision was made in the breast. While viewing the lesion usingultrasound, an early embodiment of the present invention was insertedinto the breast with the tissue receiving opening adjacent the lesion.The cutter was engaged to sample and/or remove the lesion. The lesionsvaried in size from 6-22 mm. The surgeon's comments are provided inTable 1. TABLE 1 Surgeon's Comments Regarding the Use of EarlyEmbodiments of the Present Biopsy Device Trial Number Surgeon's Comments1 Went very well, lesion took approximately 50 seconds to go away 2Large fatty breast, very difficult to get needle to mass; eventuallysuccessfully removed 3 Successfully removed without problems 4 Went verywell; lesion gone in 4-5 cores 5 Two lesions attempted (1) lesion easilyremoved, (2) inner cutter was riding up and catching the opening 6 Onlytook 4-5 cores to disappear 7 Started getting good cores, then stoppedcutting due to secondary electrical break 8 Lesion appeared to betotally gone, cores were up to 25 mm in length 9 Only got 4-5 goodcores, then stopped cutting due to inner cutter riding up 10 No problems11 No problems at all 12 Lesion was easily palpable but very mobilewhich made access difficult. Used tactile sensation to manipulate tumorinto aperture which worked very well; very good cores; Took 4.5 minutesbut many of the cores were fatty as a lot of the time I was missing thelesion before realizing that palpitation was better 13 Took 3-4 coresthen quit cutting, blade was dulled, probably due to deflection of tipdownward 14 Went very well, no problems 15 Went well, no problems 16Went well, no problems 17 Went very well 18 Went very well, the suctiontubing collapsed, need stronger tubing; filter did fill up requiringstopping to empty, might need larger filter

Table 1 illustrates the success of the present invention in its earlystage of development. A majority of the trials, trials 1-6, 8, 1-12, and14-18, resulted in a successful removal of the lesion with little to noproblems. Lesions were removed quickly and, in some cases, only a fewcores were required (see trials 1, 4, and 6). In trial number 8 it wasnoted that the cores were up to 25 mm in length.

In some trials, the surgeon experienced difficulties removing the lesionbecause the inner cutting blade would ride up and catch on the tissuereceiving opening (see trials 5, and 9,). However, this problem has beenresolved in the present invention by integrating a crimp in the outercannula. The crimp forms a dimple that protrudes from the inner surfaceof the cannula and into the outer lumen. As the inner cannula passes thedimple, the dimple forces the inner cannula away from thetissue-receiving opening and prevents the inner cannula from riding upinto the opening. In a further embodiment, the cutting edge of the innercannula is inwardly beveled. This inwardly beveled surface also helpseliminate risk of catching by guiding the inner cannula back into thehollow outer cannula. In addition, to prevent the deflection of the tipdownward, as noted in trial 13, a stiffening element is provided on theouter cannula opposite the tissue-receiving opening.

Example 2

Surgeons performing biopsies using the device of this invention and adevice having the features of U.S. Pat. No. 5,526,822 to Burbankprovided feedback as to the efficiency of each device. The surgeons'input was used to calculate the amount of time and the number of strokesnecessary to remove a lesion. Table 2 compares the amount of time andthe number of strokes necessary to remove comparable lesions using eachdevice. TABLE 2 Comparison of Removal Times and Number of Strokes of thePresent Biopsy Device with the Prior Art Device Present Biopsy DevicePrior Art Removal Times (sec) Lesion Diameter 10 80 500 13 135 845 16205 1280 No. of Strokes Lesion Diameter 10 16 25 13 27 42 16 41 64

This data demonstrates that the present tissue biopsy apparatusconsistently removes a lesion with fewer strokes and in less time thanthe prior cutter. The present tissue biopsy device performs 80% fasterthan the prior cutter, which ultimately results in reduced trauma to thetissue.

CONCLUSION

The biopsy devices of this invention reliably, quickly and efficientlysample and remove lesions in tissue.

1. (canceled)
 2. A tissue cutting device comprising: an outer cannuladefining a tissue-receiving opening adjacent a distal end thereof; aninner cannula slidably disposed within said outer cannula and defining alumen fron an open distal end to an open opposite proximal end, saidinner cannula further defining a cutting edge at said open distal end; amotor assembly operably coupled to said inner cannula for rotationallyand reciprocatingly driving said inner cannula within said outercannula; and a cutting board disposed at said distal end of said outercannula, said cutting board formed of a resilient plastic materialhaving a hardness less than a hardness of said inner cannula at saidcutting edge but sufficient to substantially prevent permanentdeformation of said cutting board under pressure from said cutting edgeas said inner cannula rotates and recoprocates against said cuttingboard.
 3. In a cannula sized for insertion in a human body, the cannulahaving a distal end and a proximal end and a substantially cylindricalouter wall defining a lumen along a longitudinal axix thereof, in whinthe lumen is sized to receive a movable cutting member therethrough, theimprovement; comprising an opening defined adjacent the distal endthrough the outer wall communicating with the lumen, said opening havingopposite edges extending along the longitudinal axis, at least one ofsaid edges defining at least one tooth arranged to engage tissue drawninto said opening when the cannula is inserted into a body.
 4. In acannula sized for insertion in a human body, the cannula having asubstantially cylindrical outer wall defining a lumen along alongitudinal axis thereof, in which the lumen is sized to receive amovable cutting member therethrough, the outer wall defining a lateralopening therethrough communicating with the lumen, the improvementcomprising a stiffening member associated with athe outer wall adjacentthe lateral opening.
 5. The improvement in a cannula according to claim4, wherein said stiffening member includes a longitudinally extendingrib defined in the outer wall.
 6. the improvement in a cannula accordingto claim 5, wherein said rib is defined substantially diametricallyopposite the lateral opening in the outer wall.
 7. In a cannula sizedfor insertion in a human body, the cannula having a substantiallycylindrical outer wall defining a lumen along a longitudinal axisthereof, in which the lumen is sized to receive a movable cutting membertherethrough, the outer wall defining a lateral opening therethroughcommunicating with the lumen, the improvement comprising a dimpleassociated with the outer waqll and projecting into the lume adjacentthe laterl opening, said dimple sized to fit between the cutting memberand the outer wall when the cutting member is within the lumen.
 8. Theimprovement in a cannula according to claim 7, wherein said dimple isformed by a crimp in the outer wall of the cannula.
 9. A tissue cuttingdevice comprising: an outer cannula defining an outer lumen and atissue-receiving opening adjacent a distal end of said outer cannulacommunicating with said outer lumen; an inner cannula slidable disposedwithin said outer lumen defining an inner lumen from an open distal endto an open opposite proximal end, said inner cannula defining a cuttingedge at said open distal end operable to sever tissue projecting throughsaid tissue-receiving opening; a first motor operably coupled to saidinner cannula to move said inner cannula in a first direction withinsaid outer lumen; means for supporting said first motor for movementwith said inner cannula in a second direction different from said firstdirection; and a second motoe operably coupled to said means forsupporting to move said first motor, and thereby said inner cannula, insaid second direction while said first motor moves said inner cannula insaid first direction.
 10. A tissue cutting device comprising: an outercannula defining an outer lumen between a distal end and an oppositeproximal end, and further defining a tissue-receiving opening adjacentsaid distal end communicating with said lumen; a cutting member slidablydisposed within said outer lumen, said cutting member defining an innerlumen therethrough between a distal end and an opposite proximal end,and further defining a cutting edge at said distal end of said cuttingmember; a handpiece supporting a drive mechanism operably coupled tosaid cutting member to move said cutting edge across saidtissue-receiving opening to sever tissue projecting therethrough; avacuum source in fluid communication with said proximal end of saidcutting member; and a hub having a distal end attached to said proximalend of said outer cannula, and a proximal end detachably mounted to saidhandpiece to permit separation of said outer cannula from said handpieceand said cutting member.
 11. (canceled)
 12. A tissue cutting systemcomprising: an outer cannula defining a tissue-receiving openingadjacent a distal end thereof; an inner cannula slidably disposed withinsaid outer cannula and defining a lumen from an open distal end to anopen oppostie proximal end, said inner cannula defining a cutting edgeat said open distal end operable to sever tissue projecting through saidtissue-receiving opening; a cuttine board disposed at said distal end ofsaid outer cannula distal from said tissue-receiving opening, saidcutting board configured to conform to said cuttting edge for impactcutting of tissue between said cutting edge and said cutting board; apiston disposed within a hydraulic cyllinder and operably coupled tosaid inner cannula to move said inner cannula within said outer cannulatoward said cutting board; a return spring disposed within said cylinderand operable against said piston to move said pistion in a directionaway from said cutting board; a source of pressurized fluid connected tosaid hydraulic sylinder having a first state providing pressurized fluidto said cyllinder and a second state permitting fluid to bleed from saidcylinder; and a pressure switch coupled to said source of pressurizedfluid to switch said source between said first state and said secondstate as a function of the magnitude of fluid pressure within saidcylinder.
 13. A tissue cutting device comprising; an outer cannuladefining a tissue-receiving opening adjacent a distal end thereof; aninner cannula slidably disposed within said outer cannula and defining alumen from an open distal end to an open opposite proximal end, saidinner cannula defining a cutting edge at said open distal end operableto sever tissue under pressure from said cutting edge against saidcutting board; a hydraulic reciprocating motor operably coupled to saidinner cannula to advance said inner cannula within said outer cannulaagainst said cutting board; and a hydraulic system connecting saidhydraulic motor to a source of pressurized fluid to provide asubstantially constant fluid pressure to said motor as said motoradvances said inner cannula. 14-49. (canceled)
 50. The tissue cuttingdevice of claim 2 wherein said cutting edge is an inwardly beveledsurface.
 51. The tissue cutting device of claim 2 further comprising atrocar tip, said trocar tip having an engagement hub configured to fittightly within said distal end of said outer cannula.
 52. The tissuecutting device of claim 51 wherein said cutting board is affixed to saidengagement hub of said trocar tip.
 53. The improvement in a cannulaaccording to claim 3 wherein said tooth is angled proximally away fromsaid distal end of said cannula.
 54. The improvement in a cannulaaccording to claim 3 wherein each of said edges defines at least onetooth, said tooth angled proximally away from said distal end ofcannula.
 55. The improvement in a cannula according to claim 3 whereineach of said edges defines a plurality of teeth, said teeth proximallyangled away from said distal end of cannula.
 56. The improvement ofclaim 5 wherein said rib includes a crimp defined in said outer cannula.57. The improvement of claim 5 wherein said rib includes a bead adheredto a said outer cannula.
 58. The improvement of claim 4 wherein saidstiffening member is a layer of rigid material bonded to a surface ofsaid outer cannula.
 59. The tissue cutting device of claim 9 whereinsaid means for supporting said first motor includes: a tubular axleextending through and supporting said first motor, having a distal endoperably connected to said proximal end of said inner cannula, and aproximal end operably coupled to said second motor to move said axle andthereby said first motor and said inner cannula in said seconddirection.
 60. The tissue cutting device of claim 9 wherein said firsstmotor is a hydraulic motor.
 61. The tissue cutting device of claim 9wherein said first motor is a rotary motor and said first direction isrotational.
 62. The tissue cutting device of claim 9 wherein said secondmotor is a linear motor and said second direction is reciprocationtoward and away from said distal end of said outer cannula.
 63. Thetissue cutting device of claim 62 wherein said second motor is ahydraulic motor.
 64. The cutting device of claim 63 wherein said secondmotor includes: a hydraulic cylinder having a pilot port in fluidconnection with a hydraulic system to receive a pressurized fluid; apiston disposed within said cylinder and operably coupled to said innercannula to move said inner cannula within said outer cannula toward saiddistal end of said outer cannula; a return spring disposed with saidcylinder and biased against said piston to move said piston and saidinner cannula within said outer cannula away from distal end of saidouter cannula.
 65. The tissue cutting device of claim 10 wherein: saidproximal end of said hub defines a mating flange; and said handpiecedefines a fitting configured for removable engagement with said matingflange.
 66. The tissue cutting device of claim 10 further comprising aradio-opaque marker disposed within said outer cannula
 67. (canceled)68. (canceled)
 69. The tissue cutting device of claim 13 furthercomprising a pressure switch coupled to said source of pressurezed toswitch from providing pressurized fluid to said motor to permittingfluid to bleed from said motor.
 70. The tissue cutting devicecomprising: an outer cannula defining an outer lumen and atissue-receiving opening adjacent a distal end of said outer cannulacommunicating with said outer lumen; an inner cannula slidably disposedwithin said outer lumen and defining a inner lumen from an opem distalend to an open opposite proximal end, said inner cannula defining acutting edge at said open distal end operable to sever tissue projectingthrough said tissue-receiving opening; and a drive mechanism operablycoupled to said inner cannula to move said inner cannula relative tosaid tissue-receiving opening in said outer cannula, wherein said drivemechanism is substantially composed of a non-metallic material.
 71. Thetissue cutting device of claim
 70. wherein said drive mechanismincludes: a first motor operable to rotate said inner cannula; and asecond motor operable to translate said inner cannula.
 72. The tissuecutting device of claim 71, wherein said first and second motors arehydraulic motors.
 73. The tissue cutting device of claim 70, whereinsaid non-metallic material is a plastic.
 74. The tissue cutting deviceof claim 70, further comprising a handpiece supporting said drivemechanism and said outer cannula.
 75. The tissue cutting mechanism ofclaim 74, wherein said handpiece is substantially composed ofnon-metallic material.
 76. The tissue cutting mechanism of claim 75,wherein said handpiece is substantially composed of a plastic material.77. The tissue cutting device of claim 75, wherein said hydraulic systemincludes said vacuum source.
 78. The tissue cutting device of claim 77,wherein said vacuum source includes a venturi device.
 79. An automatedmethod for removing tissue from a patient comprising the steps of:introducing a tissue removal device into the patient adjacent the tissueremoval site, the tissue removal device including an outer cannuladefining a tissue-receiving opening, an inner cannula moveably disposedwithin the outer cannula and defining a lumen from an open distal end toan open opposite proximal end, and a collection trap for storing excisedtissue, the tissue removal device operable to sever tissue projectingthrough the tissue-receiving opening and to aspirate the excised tissuethrough the lumen into the collection trap; providing the tissue removaldevice in communication with a control system, the control systemoperable to control excision, aspiration and storage of a tissue samplein response to a single authorization step; and authorizing the controlsystem to remove a tissue sample.
 80. The methond of claim 79, whereinthe authorization step comprises acutuating a single switch.
 81. Amethod for removing tissue from a patient comprising the steps of;providing a tissue removal device that includes an outer cannuladefining at tissue receiving opening, an inner cannula moveably disposedwithin the outer cannula and defining a lumen from an open distal end toan open opposite proximal end, the inner cannula operable to severtissue projecting through the tissue-receiving opening; providing amagnetic resonance imaging device to create an image of the targettissue to be removed; introducing the outer cannula into the patientwith the tissue receiving opening adjacent the tissue removal site; andsimultaneously creating an image of the target tissue using the magneticresonance imaging device and operating the tissue removal device toremove the target tissue through the tissue receiving opening.
 82. Amethod for removing tissue from a patient comprising the steps of:providing a tissue removal device that includes an outer cannuladefining a tissue-receiving opening, an inner cannula moveably disposedwithin the outer cannula and defining a lumen from an open distal end toan open opposite proximal end, and a collection trap, the inner cannulaoperable to sever tissue projecting through the tissue-receiving openingand to direct the excised tissue toward the storage unit; introducingthe outer cannula into the patient with the tissue receiving openingadjacent the tissue removal site; operating the tissue removal device toexcise a tissue sample through the tissue receiving opening;continuously applying an aspirating vacuum during operation of thetissue removal device to draw the excised tissue through the lumen intothe collection trap; and storing the excised tissue in the collectiontrap for subsequent examination.
 83. The method of claim 82, wherein thestep of continuously applying the aspirating vacuum is further definedby drawing the tissue sample into the tissue receiving opening using theaspirating vacuum prior to excising the tissue sample.
 84. The method ofclaim 82, further comprising the step of operating the tissue removaldevice to excise at least one additional tissue sample prior to removingthe stored excised from the collection trap.